Fix a typo in the documentation
Fix a typo in the documentation

Thanks to Reiner Dolp for reporting it.

Fixes #229

vsmontalvao/liblouis,BueVest/liblouis,BueVest/liblouis,IndexBraille/liblouis,hammera/liblouis,liblouis/liblouis,IndexBraille/liblouis,hammera/liblouis,BueVest/liblouis,hammera/liblouis,BueVest/liblouis,hammera/liblouis,liblouis/liblouis,hammera/liblouis,vsmontalvao/liblouis,hammera/liblouis,IndexBraille/liblouis,vsmontalvao/liblouis,liblouis/liblouis,BueVest/liblouis,liblouis/liblouis,vsmontalvao/liblouis,IndexBraille/liblouis,liblouis/liblouis,BueVest/liblouis,vsmontalvao/liblouis,IndexBraille/liblouis,liblouis/liblouis